U.S. patent number 5,881,727 [Application Number 08/583,939] was granted by the patent office on 1999-03-16 for integrated cardiac mapping and ablation probe.
This patent grant is currently assigned to EP Technologies, Inc.. Invention is credited to Stuart D. Edwards.
United States Patent |
5,881,727 |
Edwards |
March 16, 1999 |
Integrated cardiac mapping and ablation probe
Abstract
A probe for cardiac diagnosis and/or treatment has a catheter
tube. The distal end of the catheter tube carries first and second
electrode elements. The probe includes a mechanism for steering the
first electrode element relative to the second electrode element so
that the user can move the first electrode element into and out of
contact with endocardial tissue without disturbing the contact of
the second electrode element with endocardial tissue, even through
the two electrode elements are carried on a common catheter tube.
The distal end can carry a three dimensional structure having an
open interior area. One of electrode elements can be steered
through the open interior area of the structure. Electrode elements
on the exterior of the structure can be used for surface mapping,
while the electrode element inside the structure is steered to
ablate tissue.
Inventors: |
Edwards; Stuart D. (Los Altos,
CA) |
Assignee: |
EP Technologies, Inc.
(Sunnyvale, CA)
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Family
ID: |
22473760 |
Appl.
No.: |
08/583,939 |
Filed: |
January 4, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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136648 |
Oct 14, 1993 |
|
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Current U.S.
Class: |
600/374; 606/41;
607/122 |
Current CPC
Class: |
A61N
1/06 (20130101); A61B 18/1492 (20130101); A61B
2018/00839 (20130101); A61B 2018/1253 (20130101); A61B
2018/00214 (20130101); A61B 2018/00577 (20130101); A61B
2018/0016 (20130101); A61B 18/1815 (20130101); A61B
2218/002 (20130101); A61B 2018/00357 (20130101) |
Current International
Class: |
A61B
18/14 (20060101); A61N 1/06 (20060101); A61B
005/0408 (); A61B 017/39 (); A61N 001/05 () |
Field of
Search: |
;128/642 ;607/122
;606/41 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cohen; Lee S.
Attorney, Agent or Firm: Lyon & Lyon LLP
Parent Case Text
This is a continuation of application Ser. No. 08/136,648 filed on
Oct. 14, 1993, now abandoned.
Claims
What is claimed is:
1. An integrated probe for use within a heart to contact tissue
comprising
a catheter tube having a distal end,
a steerable supporting body integrally attached to and extending
distally beyond the distal end of the catheter tube, the steerable
supporting body having a distal region,
a first electrode element carried on the steerable supporting body
for contact with tissue,
a support structure attached to and extending distally beyond the
distal end of the catheter tube, the support structure being of a
three dimensional form having an open interior, within which the
steerable supporting body is located with the distal region of the
steerable supporting body being detached from the support
structure,
a second electrode element carried by the support structure,
and
a mechanism to steer the steerable supporting body to move the
first electrode element relative to the second electrode
element.
2. A probe according to claim 1
wherein at least one of the first and second electrode elements is
operative for emitting energy to ablate myocardial tissue.
3. A probe according to claim 1
wherein at least one of the first and second electrode elements is
operative for sensing electrical activity in endocardial
tissue.
4. A probe according to claim 1
wherein one of the first and second electrode elements is operative
for sensing electrical activity in endocardial tissue, and
wherein the other one of the first and second electrode elements is
operative for emitting energy to ablate myocardial tissue.
5. A probe according to claim 1
wherein at least one of the first and second electrode elements is
operative in a first mode for sensing electrical activity in
endocardial tissue and in a second mode for emitting energy to
ablate myocardial tissue.
6. A probe for use within the heart to contact tissue
comprising
a catheter tube having a proximal end and a distal end,
a handle attached to the proximal end,
a three dimensional structure on the distal end having an open
interior area, the structure having an exterior surface for
contacting tissue,
a steerable electrode support carrying at least one electrode
element and extending from the distal end of the catheter tube into
the open interior area of the structure, the steerable electrode
support having a movable distal end which is detached from the
three dimensional structure, the steerable electrode support and
the three dimensional structure both being integral with the
catheter tube, and
a mechanism on the handle to steer the steerable electrode support
within the open interior area.
7. A probe according to claim 6
and further including a mechanism to collapse the three dimensional
structure to close the open interior area and to expand the three
dimensional structure to open the open interior area.
8. A probe according to claim 6
and further including a second electrode element on the exterior
surface of the structure.
9. A probe according to claim 8
wherein at least one of the first and second electrode elements is
operative for sensing electrical activity in endocardial
tissue.
10. A probe according to claim 8
wherein at least one of the first and second electrode elements is
operative for emitting energy to ablate myocardial tissue.
11. A probe according to claim 6
wherein the at least one electrode element is operative for
emitting energy to ablate myocardial tissue.
12. A probe according to claim 6
and further including a second electrode element on the exterior
surface operative for sensing electrical activity in endocardial
tissue.
13. A probe according to claim 12
wherein the first mentioned electrode element is operative for
emitting energy to ablate myocardial tissue.
14. A probe according to claim 13
wherein the second electrode element is further operative for
emitting energy to ablate myocardial tissue.
15. A probe for use within a living body comprising
a catheter tube having a proximal end and a distal end,
a handle attached to the proximal end,
a three dimensional structure on the distal end having an open
interior area, the structure having an exterior surface for
contacting tissue within the living body,
a steerable support body carrying at least one ablating element and
extending from the distal end of the catheter tube into the open
interior area of the structure, the steerable support body having a
movable distal end which is detached from the three dimensional
structure, the steerable support body and the three dimensional
structure both being integral with the catheter tube, and
a mechanism on the handle to steer the steerable support body
within the open interior area.
Description
FIELD OF THE INVENTION
The invention relates to systems and methods for mapping and
ablating the interior regions of the heart for treatment of cardiac
conditions.
BACKGROUND OF THE INVENTION
Physicians make use of catheters today in medical procedures to
gain access into interior regions of the body to ablate targeted
tissue areas. It is important for the physician to be able to
carefully and precisely control the position of the catheter and
its emission of energy within the body during tissue ablation
procedures.
The need for careful and precise control over the catheter is
especially critical during procedures that ablate tissue within the
heart. These procedures, called electrophysiological therapy, are
becoming more widespread for treating cardiac rhythm
disturbances.
During these procedures, a physician steers a catheter through a
main vein or artery into the interior region of the heart that is
to be treated. The physician then further manipulates a steering
mechanism to place the electrode carried on the distal tip of the
catheter into direct contact with the tissue that is to be ablated.
The physician directs energy from the electrode through tissue to
an indifferent electrode (in a uni-polar electrode arrangement) or
to an adjacent electrode (in a bi-polar electrode arrangement) to
ablate the tissue and form a lesion.
Cardiac mapping can be used before ablation to locate aberrant
conductive pathways within the heart. The aberrant conductive
pathways constitute peculiar and life threatening patterns, called
dysrhythmias. Mapping identifies regions along these pathways,
called foci, which are then ablated to treat the dysrhythmia.
There is a need for cardiac mapping and ablation systems and
procedures that can be easily deployed with a minimum of
manipulation and effort.
There is also a need for systems and procedures that are capable of
performing cardiac mapping in tandem with cardiac ablation. Such
multipurpose systems must also be easily introduced into the heart.
Once deployed, such multipurpose systems also must be capable of
mapping and ablating with a minimum of manipulation and effort.
SUMMARY OF THE INVENTION
A principal objective of the invention is to provide improved
probes to carry out cardiac mapping and/or cardiac ablation
procedures quickly and accurately.
Another principal objective of the invention is to provide improved
probes that integrate mapping and ablation functions.
One aspect of the invention provides a probe having a catheter
body. The distal end of the catheter body carries first and second
operative elements. In use, the operative elements make contact
with endocardial tissue independently of each other to perform
therapeutic or diagnostic functions. According to this aspect of
the invention, the probe includes a mechanism for steering the
first operative element without altering the position of the second
operative element.
According to this aspect of the invention, the user can move the
first electrode element into and out of contact with endocardial
tissue without disturbing the contact of the second electrode
element with endocardial tissue, even though the two electrode
elements are carried on a common catheter body. This aspect of the
invention permits the first and second operative elements to
perform the same or different functions.
For example, in a preferred embodiment, the first operative element
serves to ablate myocardial tissue. The second operative element
independently serves to sense electrical activity in endocardial
tissue.
In this arrangement, the second operative element comprises one or
more electrodes that map endocardial tissue to locate foci to be
ablated. The first operative element can be steered to the foci
located by the mapping electrodes, without interfering with their
mapping function.
In one preferred embodiment, the second operative element can be
operated to ablate myocardial tissue by thermal or chemical means,
independently of the mapping function performed by the first
electrode element.
In another aspect of the invention, the distal end of the catheter
body carries a three dimensional structure having an open interior
area. The structure has an exterior surface for contacting
endocardial tissue. According to this aspect of the invention, the
probe includes an operative element that extends from the distal
end of the catheter body into the open interior area of the
structure. The probe includes a mechanism for steering the
operative element through the open interior area.
This aspect of the invention provides a three dimensional structure
that surrounds the operative element to stabilize its position
during use. The user can steer the operative element through the
stabilizing structure to make selected contact with endocardial
tissue.
In a preferred embodiment, the operative element ablates myocardial
tissue. In this arrangement, the ablating element can take the form
of an electrode that thermally destroys myocardial tissue.
Alternatively, the ablating element can inject a chemical substance
that destroys myocardial tissue.
In a preferred embodiment, the exterior surface of the structure
carries electrode elements for sensing electrical activity in
endocardial tissue. In this arrangement, the exterior electrode
elements can be used to map the surface of endocardial tissue,
while the interior element can be independently steered into
position to ablate the tissue. This aspect of the invention
provides a probe that integrates mapping and ablation
functions.
Other features and advantages of the inventions are set forth in
the following Description and Drawings, as well as in the appended
Claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a probe and monitoring system that
embodies the features of the invention;
FIG. 2 is a plan view of the interior of the handle for the
steerable catheter, partially broken away and in section, showing
the mechanism for steering the distal tip of the catheter body;
FIG. 3 is a plan view showing the exterior of the handle of FIG.
2;
FIG. 4 is a fragmentary side cross sectional view of the handle of
taken along Line 4--4 of FIG. 3;
FIG. 5 is a fragmentary sectional view on a greatly enlarged scale
showing the mapping electrode deployment mechanism;
FIG. 6 is a plan view of an electrode-carrying basket and movable
guide sheath shown in FIG. 1, with portions fragmented and in
section, showing the electrode-carrying basket in a retracted
condition;
FIG. 7 is a plan view of the handle showing the mapping basket
control in the deployed position;
FIG. 8 is a view, partially broken away and in section, showing the
guide sheath and the steerable catheter body advanced into the
deployment position;
FIG. 9 is a plan view of the handle showing the mapping basket
control in the deployed position illustrating use of the steering
control mechanism to steer the ablation catheter;
FIG. 10 is a view, partially broken away and in section, showing
the guide sheath and the steerable catheter body advanced into the
deployment position with the ablation electrode steered into
position for use;
FIG. 11 is a plan view of the handle illustrating steering of the
probe with the electrode-carrying basket retracted; and,
FIG. 12 is an enlarged plan view of probe distal tip illustrating
steering of the probe with the electrode-carrying basket
retracted.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows an endocardial mapping system 10 that embodies
features of the invention.
The system 10 includes a catheter probe 12.
The catheter probe 12 includes a handle 14, to which a flexible
guide body 16 is attached.
The distal end of the guide body 16 carries a three dimensional
structure 18. The structure 18 takes the form of a basket, as best
shown in FIGS. 8 and 10.
The three dimensional basket structure 18 includes an exterior
surface 28 that encloses an open interior area 30. The basket
structure 18 carries a three dimensional array of electrodes 32 on
its exterior surface 28. When deployed inside the heart chamber,
the exterior surface 28 of the basket structure 18 holds the
electrodes 32 against the endocardial surface.
According to the invention, the three dimensional structure 18
carries within it a steerable ablating element 20. The ablating
element 20 is moveable through the interior area 20 without
requiring movement of the structure 18 itself.
As FIG. 5 best shows, the guide body 16 comprises a multi-layer
tubular construction. It includes at its core a length of stainless
steel coiled into a flexible spring 22 enclosing an interior bore
24. A braided sheath 26 of plastic material surrounds the guide
spring 22.
As FIG. 5 also shows, the guide body 16 also includes an outer
sheath 34 that surrounds the inner sheath 26. The outer sheath 34
is made from an inert plastic material, which, in the preferred
embodiment, comprises a nylon composite material. The sheath 34 has
an inner diameter that is greater than the outer diameter of the
inner sheath 26. As a result, the outer sheath 34 can slide along
the inner sheath 26.
The handle 14 carries a control knob 36, which is attached to the
sheath 16 (see FIGS. 2 to 4). Forward movement of a control knob 36
(see FIG. 11) advances the distal end of the slidable sheath 34
upon the basket structure 18. The slidable sheath 34 captures and
collapses the basket structure 18 (as FIGS. 6 and 12 show). In this
position, the distal end of the sheath 34 entirely encloses the
basket structure 18. The physician introduces the basket structure
18 into the selected heart chamber through a selected vein or
artery when in this collapsed, low profile condition.
Rearward movement of the control knob 36 (see FIGS. 7 and 8)
retracts the slidable sheath 34 away from the basket structure 18.
The basket structure 18 opens to assume its prescribed three
dimensional shape, as FIG. 8 shows. The basket structure 18 is
thereby deployed for use within the heart chamber.
The basket 18 can be variously constructed. In the illustrated and
preferred embodiment (best shown by FIGS. 9 and 11), the basket 24
comprises an annular base member 38 attached about the inner sheath
26. The basket 24 also includes an end cap 40.
Generally flexible splines 42 extend in a circumferentially spaced
relationship between the base member 38 and the end cap 40. In the
illustrated embodiment, six splines 42 form the basket 18. However,
additional or fewer splines 42 could be used, depending upon the
application.
In this arrangement, the splines 42 are made of a resilient inert
material, like Nitinol metal or silicone rubber. The splines 42 are
connected between the base member 38 and the end cap 40 in a
resilient, pretensed condition, as shown in FIG. 10. In this
configuration, the resilient splines 42 bend and conform to the
tissue surface they contact.
As FIGS. 6 and 12 show, the splines 42 also collapse into a closed,
compact bundle in response to an external compression force, which
the external sheath 34 provides.
In the illustrated embodiment (as FIG. 8 shows), each spline 42
carries six electrodes 32. Of course, additional or fewer
electrodes 32 can be used. In the preferred embodiment, the
electrodes 32 are made of platinum or gold plated stainless
steel.
Signal wires 44 made from a highly conductive metal, like copper,
lead from the electrodes 32. The signal wires 44 extend down the
associated spline 42, through the base member 38, and into the bore
24 of the guide spring 22 (see FIGS. 5 and 6). An inert plastic
electrically insulating sheath preferably covers each spline 42 to
also enclose the signal wires 44. In the preferred embodiment, the
sheath is made of a polyurethane elastomer.
The six signal wires 44 for each spline 42 are twisted together to
form a common bundle 46 (see FIGS. 5 and 6). As FIGS. 5 and 6 show,
the common bundle 46 is, in turn, passed through the bore 24 of the
guide spring 22 and into the probe handle 14 (see FIG. 2).
The thirty six signal wires 44 attach via a signal cable to an
external controller 50, as FIG. 1 shows.
When deployed, the electrodes 32 record the electrical potentials
in myocardial tissue. The controller 50 derives the activation
times, the distribution, and the waveforms of the potentials
recorded by the basket electrodes 32. As FIG. 1 shows, displays 52
can be provided to indicate electrical potential measurements at
each electrode 32.
In an alternative arrangement, ablating energy can be applied
through a selected one or more of the basket electrodes 32.
In the illustrated and preferred embodiment, the movable ablating
element 20 is an integral part of the probe 18. The type of
ablating energy used can vary. The physician can ablate tissue by
using an electrode to thermally destroy myocardial tissue, either
by heating or cooling the tissue. Alternatively, the physician can
inject a chemical substance that destroys myocardial tissue. The
physician can use other means for destroying myocardial tissue as
well.
In the illustrated embodiment, the ablating element 20 takes the
form a coaxial antenna assembly that emits electromagnetic
microwave energy. The ablating antenna assembly 20 extends beyond
the distal end of the guide spring 22 and its associated inner
sheath 26.
The details of the microwave antenna assembly 20 and its attachment
to the guide spring 22 are shown in copending application Ser. No.
07/868,031, filed Apr. 13, 1992, entitled "Steerable Antenna
Systems for Cardiac Ablation that Minimize Tissue Damage and Blood
Coagulation Due to Conductive Heating Patterns," which is
incorporated herein by reference.
The ablating antenna assembly 20 includes an antenna 54 (see FIG.
6). The antenna 54 forms a helix with about 10 turns. Based upon
its size and helical pattern, the operating frequencies of the
antenna 54 is either about 915 MHz or 2450 Mhz.
The antenna assembly 20 includes an associated coaxial cable 56.
The cable 56 extends from within the handle 14 (see FIG. 2) along
the outside of the guide spring 22 and within the sheath 32 (see
FIG. 5). A supply cable 58 (see FIGS. 1 and 2) is joined to the
proximal end of the antenna cable 56. The supply cable 58 conducts
microwave ablating energy from the controller 50 to the antenna 54
for propagation at the lesion site.
The ablating antenna assembly 20 includes its own steering assembly
74. The steering mechanism 74 for the ablating antenna assembly 20
may vary. In the illustrated embodiment, the steering mechanism 74
is of the type shown in copending application Ser. No. 07/868,031,
which is identified above and which is also incorporated herein by
reference.
In the illustrated embodiment (see FIG. 2), the steering mechanism
74 includes an interior cam wheel 76 located within the handle 14.
An external steering lever 78 (see FIG. 3) rotates the cam wheel
76. The cam wheel 76 holds the proximal ends of right and left
steering wires 80.
As FIG. 2 shows, steering wires 80 extend from the associated left
and right side surfaces of the cam wheel 76. The steering wires 80
extend through the bore 24 guide spring 22 (see FIG. 5) to the
ablating antenna assembly 20.
The steering wires 80 attach to opposite sides to a steering spring
60 (see FIG. 6). The steering spring 60 is, in turn, soldered to
the distal end of the antenna cable 56.
The helix antenna 54 extends distally from this juncture, being
enclosed within a shroud 62 of potting compound. The potting
compound shroud 62 preferable includes a particles of diamond or
sapphire that provide a high dielectric constant; low microwave
energy loss; and high thermal conductivity.
When the ablation element 20 is deployed out of the sheath 34 (as
FIGS. 9 and 10 show), forward movement of the steering lever 78
bends the ablation element 20 down (as shown in phantom lines)
while rearward movement bends the ablation element 20 up (as shown
in solid lines). The element 20 moves through the basket 18 between
a generally straight configuration (as FIG. 8 shows) and the up and
down deflected positions (as FIGS. 9 and 10 show), to selectively
place the ablating element 20 in contact with endocardial
tissue.
By manipulating the steering lever 78, the physician can maneuver
the ablating element 20 under fluoroscopic control through the
basket 18 into contact with any point of the endocardial surface of
the chamber. The ablating element 20 can be moved through the
basket 18 to tissue locations either in contact with the exterior
surface of the basket 18 or laying outside the reach of the basket
18 itself. Ablating energy can then be applied to thermally destroy
the tissue.
Furthermore, as FIGS. 11 and 12 show, by manipulating the steering
lever 78 when the outer sheath 34 is moved forward, the physician
can maneuver or steer the entire distal tip of the probe 18 during
its introduction into the selected heart chamber.
Various features of the invention are set forth in the following
claims.
* * * * *